Generally, vehicles are manufactured such that a linear movement, that is generated when a fuel mixed with an air in an appropriate ratio is inhaled into a cylinder, compressed, ignited, and exploded, is converted into a rotational movement having a torque using a connecting rod and a crank, and thereby the vehicles can be operated by the driving force.
The engines of these vehicles are designed to combust their fuels, whether they are gasolines or diesels, smoothly so that the air introduced from the air filter is purified by the filter, naturally mixed with the fuel being sprayed, and then sprayed into a carburetor or sprayer, thereby providing the locomotive power for the operation of the vehicles.
The combustion gas generated by the ignition of the fuel is collected into one place through an exhaust manifold of an engine, and carbon monoxide, hydrocarbons, nitrogen oxides, etc., are reduced by catalysts while they pass through a catalytic converter, and the combustion gas being introduced into a sub-muffler in a reduced state, passes through a muffler having multiple baffles and thereby the noise becomes reduced and the combustion gas is exhausted to the outside.
However, the exhaust pipe through which the combustion gas passes consists of a simple circular linear pipe and thus the exhaust resistance is directly applied into the inside of the exhaust pipe thereby making a smooth exhaustion of the combustion gas difficult and raising problems such as deterioration in output, increase of fuel cost, loss of engine power itself, etc.
As described above, a smooth exhaust power of a combustion gas in an exhaust apparatus has an important impact on vehicle performances, such as power, fuel efficiency, etc. Conventionally, the exhaust pipe in an exhaust apparatus consisted of a simple linear pipe and thus simply served the role of guiding the exhausted combustion gas to the outside of the vehicle, and thus there was a need for the improvement of a further increase of the exhaust power of the combustion gas for the improvement of the engine power.
Additionally, the insertion of a rifling in a coil spring form into the inside of the exhaust to cause a circulation phenomenon within the inside of an exhaust pipe. However, it was configured such that the combustion gas, that passes through the inside of the exhaust pipe, collides with the rifling and turn along the spring and it only generated a very weak circulation phenomenon. That is, the combustion gas that passes through the core of the coil spring is allowed to freely without a circulation phenomenon, and as a result, the two streams, i.e., a stream of colliding with the rifling and turns around the rifling and a stream that directly passes through the core hinder with each other thereby significantly slowing the flow rate and preventing the generation of an active circulation phenomenon over the entire interior of the exhaust pipe thus having of little effect.